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May 1964

Roentgenologic Bone Changes in Phenylketonuria: Relation to Dietary Phenylalanine and Serum Alkaline Phosphatase

Am J Dis Child. 1964;107(5):523-532. doi:10.1001/archpedi.1964.02080060525013

Introduction  Recently, Feinberg and Fisch 1 described the presence of calcified spicules projecting into the epiphyseal area of the long bones in some patients with phenylketonuria. These spicules were described as dense, blunt projections, associated with early cupping of the metaphysial plate. With bone growth this cupping disappeared and the spicules shortened, broadened, and were incorporated into the metaphysial spongiosa. Ultimately, they were seen in the diaphysis. The changes differ from rickets in that they occur earlier (as early as 3 months of age), there is no dissolution or fraying of the metaphysial plate of the epiphysis, the metaphysis does not vanish, and the spicules are more coarse.These authors described five patients who demonstrated "strongly positive" roentgenologic changes while receiving 15-30 mg/kg/day of phenylalanine and maintaining a serum phenylalanine level below 8 mg/100 ml. Four patients with "less positive" changes were either not on the diet or inadequately